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FREE INSTITUTE OF SCIENCE 
VEGETATION OF SOUTH FLORIDA 
area would soon form a sandy marl loam, which is actually the character of 
the soil in the big hammock south of Miami. Once mesophytic conditions 
are established by the enrichment of the soil through the deposit of vegetal 
material, the complete shading of the soil by the dense tangle of trees, lianes 
and other plants, would make self-perpetuative these conditions and the 
subsequent successions would be concerned with the broad-leaved sub- 
tropic and tropic forest vegetation. The shading of the soil and the in- 
crease in the amount of spongy humus would increase the retentivity of the 
soil to moisture, and in time, the surface of the hammock would be raised by 
plant growth above the general surface of the surrounding pineland, where 
the accumulation of humus is extremely slow owing to the rapid desiccation 
of the forest litter. Such an hypothesis probably explains the origin of 
other Florida hammocks beside the celebrated one near Miami. 
Geographic Location of Banana Holes.—The sinks, or banana holes of 
South Florida, are located in the region covered by Miami oólite and especi- 
ally in the district south of Rockdale, a station on the Florida East Coast 
Railroad, south of Miami. From Rockdale south to Homestead and 
Detroit, the banana holes become more frequent, but undisturbed examples 
are not found until after passing Naranja (Text Fig. 1), because the settlers 
of the region between Rockdale and Naranja have utilized all of the existing 
banana holes in the raising of tender plants, which have occupied the sink 
during the entire period of their growth, or have been transplanted to the 
prairie, or pineland, after they have passed the tender seedling condition. The 
farmers of the region use the banana holes to start their market vegetables, 
instead of the usual hot beds characteristic of such market gardening in the 
northern states. One of these banana holes at Goulds was filled with cotton. 
Another was occupied by growing Kaffir corn, while another was marked 
by the presence of a group of dwarf bananas, probably Musa Cavendishii 
Lambert. Much of the prairie and pine soils of the region are being used in 
the growth of early tomatoes for the northern market. In the north, as the 
tomato requires a warm soil and climate, a sunny position and long season, 
the plants are usually started in hot beds, or glass houses, being transferred 
to the open as soon as settled weather permits. In the region of Florida where 
banana holes are common, tomatoes are started in them, where they are pro- 
tected from occasional frosts, and afterward they are transplanted for open 
field culture. 
